/*
 * Copyright (C) 2013 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.aplink.generic.google.datetimepicker;

import java.util.Calendar;

import android.animation.Keyframe;
import android.animation.ObjectAnimator;
import android.animation.PropertyValuesHolder;
import android.annotation.SuppressLint;
import android.os.Build;
import android.text.format.Time;
import android.view.View;

/**
 * Utility helper functions for time and date pickers.
 */
public class Utils {

    // Alpha level for fully opaque.
    public static final int FULL_ALPHA = 255;
    public static final int MONDAY_BEFORE_JULIAN_EPOCH = Time.EPOCH_JULIAN_DAY - 3;

    public static final int PULSE_ANIMATOR_DURATION = 544;
    // Alpha level for time picker selection.
    public static final int SELECTED_ALPHA = 51;
    public static final int SELECTED_ALPHA_THEME_DARK = 102;

    static final String SHARED_PREFS_NAME = "com.android.calendar_preferences";

    public static int getDaysInMonth(final int month, final int year) {
        switch (month) {
        case Calendar.JANUARY:
        case Calendar.MARCH:
        case Calendar.MAY:
        case Calendar.JULY:
        case Calendar.AUGUST:
        case Calendar.OCTOBER:
        case Calendar.DECEMBER:
            return 31;
        case Calendar.APRIL:
        case Calendar.JUNE:
        case Calendar.SEPTEMBER:
        case Calendar.NOVEMBER:
            return 30;
        case Calendar.FEBRUARY:
            return ((year % 4) == 0) ? 29 : 28;
        default:
            throw new IllegalArgumentException("Invalid Month");
        }
    }

    /**
     * Takes a number of weeks since the epoch and calculates the Julian day of
     * the Monday for that week.
     * 
     * This assumes that the week containing the {@link Time#EPOCH_JULIAN_DAY}
     * is considered week 0. It returns the Julian day for the Monday
     * {@code week} weeks after the Monday of the week containing the epoch.
     * 
     * @param week
     *            Number of weeks since the epoch
     * @return The julian day for the Monday of the given week since the epoch
     */
    public static int getJulianMondayFromWeeksSinceEpoch(final int week) {
        return Utils.MONDAY_BEFORE_JULIAN_EPOCH + (week * 7);
    }

    /**
     * Render an animator to pulsate a view in place.
     * 
     * @param labelToAnimate
     *            the view to pulsate.
     * @return The animator object. Use .start() to begin.
     */
    public static ObjectAnimator getPulseAnimator(final View labelToAnimate,
            final float decreaseRatio, final float increaseRatio) {
        final Keyframe k0 = Keyframe.ofFloat(0f, 1f);
        final Keyframe k1 = Keyframe.ofFloat(0.275f, decreaseRatio);
        final Keyframe k2 = Keyframe.ofFloat(0.69f, increaseRatio);
        final Keyframe k3 = Keyframe.ofFloat(1f, 1f);

        final PropertyValuesHolder scaleX = PropertyValuesHolder.ofKeyframe(
                "scaleX", k0, k1, k2, k3);
        final PropertyValuesHolder scaleY = PropertyValuesHolder.ofKeyframe(
                "scaleY", k0, k1, k2, k3);
        final ObjectAnimator pulseAnimator = ObjectAnimator
                .ofPropertyValuesHolder(labelToAnimate, scaleX, scaleY);
        pulseAnimator.setDuration(Utils.PULSE_ANIMATOR_DURATION);

        return pulseAnimator;
    }

    /**
     * Returns the week since {@link Time#EPOCH_JULIAN_DAY} (Jan 1, 1970)
     * adjusted for first day of week.
     * 
     * This takes a julian day and the week start day and calculates which week
     * since {@link Time#EPOCH_JULIAN_DAY} that day occurs in, starting at 0.
     * *Do not* use this to compute the ISO week number for the year.
     * 
     * @param julianDay
     *            The julian day to calculate the week number for
     * @param firstDayOfWeek
     *            Which week day is the first day of the week, see
     *            {@link Time#SUNDAY}
     * @return Weeks since the epoch
     */
    public static int getWeeksSinceEpochFromJulianDay(final int julianDay,
            final int firstDayOfWeek) {
        int diff = Time.THURSDAY - firstDayOfWeek;
        if (diff < 0) {
            diff += 7;
        }
        final int refDay = Time.EPOCH_JULIAN_DAY - diff;
        return (julianDay - refDay) / 7;
    }

    public static boolean isJellybeanOrLater() {
        return Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN;
    }

    /**
     * Try to speak the specified text, for accessibility. Only available on JB
     * or later.
     * 
     * @param text
     *            Text to announce.
     */
    @SuppressLint("NewApi")
    public static void tryAccessibilityAnnounce(final View view,
            final CharSequence text) {
        if (Utils.isJellybeanOrLater() && (view != null) && (text != null)) {
            view.announceForAccessibility(text);
        }
    }
}
